创建使用 whois 的套接字

Question

这是我从 获得的一个程序Java Complete Reference: 7th Edition。稍作修改：

import java.net.*;
import java.io.*;

public class WhoIs {
    public static void main(String[] args) throws Exception{
        Socket s = new Socket("internic.net",43);

        OutputStream os = s.getOutputStream();
        String domain = "facebook.com"+"\n";
        byte[] stringToByte = domain.getBytes();
        os.write(stringToByte);

        InputStream is = s.getInputStream();
        InputStreamReader reader = new InputStreamReader(is);
        BufferedReader buf = new BufferedReader(reader);

        String temp;
        while((temp=buf.readLine())!="\n"){
            System.out.println(temp);
        }
    }
}  

它只是联系internic.net并获取有关 Facebook 的信息。但是，套接字无法连接。我得到一个异常如下：

Exception in thread "main" java.net.ConnectException: Connection refused: connect
    at java.net.DualStackPlainSocketImpl.connect0(Native Method)
    at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
    at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
    at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
    at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
    at java.net.PlainSocketImpl.connect(Unknown Source)
    at java.net.SocksSocketImpl.connect(Unknown Source)
    at java.net.Socket.connect(Unknown Source)
    at java.net.Socket.connect(Unknown Source)
    at java.net.Socket.<init>(Unknown Source)
    at java.net.Socket.<init>(Unknown Source)
    at javacomplete.WhoIs.main(WhoIs.java:8)  

除了读回数据之外，一切都和书上一模一样。我用的是a BufferedReader，这本书用来InputStream读单个字符。

帮助！为什么连接不上？？

Answer 1

正确的主机名是whois.internic.net而不是internic.net：

$ telnet internic.net 43
Trying 192.0.43.9...
telnet: connect to address 192.0.43.9: Connection refused
Trying 2001:500:88:200::9...
telnet: connect to address 2001:500:88:200::9: No route to host
telnet: Unable to connect to remote host

$ telnet whois.internic.net 43
Trying 199.7.56.74...
Connected to whois.internic.net.
Escape character is '^]'.